1. Field of the Invention
The present invention relates to high resolution optical scanners and, more particularly, to a high resolution scanning mechanism for use in a conventional optical scanner.
2. Description of the Related Art
Optical scanners are typically used to electronically reproduce visually perceptible images on materials, such as documents, photographs and transparencies, in a digital format for use by a computer. Once images have been stored on a computer, they may be altered and reproduced for any purpose, including the reproduction of high definition imaging for use in multimedia-type applications.
Optical scanners are available in a variety of configurations, tailored to the needs of the user. For example, low resolution, high speed scanners are used by many businesses for the electronic transfer of documents over local area networks and telephone lines using facsimile machines. A conventional scanner includes a light-receiving device mounted in a light-receiving seat. The seat is coupled to a pair of rails and is movably adjusted along the rails for scanning line-by-line documents, photographs, transparencies, etc. The light-receiving device includes mirrors and a lens for focusing the image upon a charge coupled device (CCD) which then converts the light images into electrical signals. These signals are then digitized for use by a computer for reproduction and manipulation of the digitized image by commercially available software. In conventional scanners, the CCD is centrally mounted within the light-receiving device. The device may also include the use of a focusing mechanism for adjusting the distance between the lens and the CCD. While these devices are suitable for low resolution document reproduction, they are unable to provide the necessary resolution required for use with multi-media and digital photographic processing applications.
High resolution optical scanners have been proposed which are generally of a high cost due to the electro-optic transducers known as CCDs, required for high resolution. CCD resolution is determined by the number optical sensors or pixels located linearly across the viewing area. These CCDs can be manufactured to obtain the desired high resolution by increasing the number of pixels per inch. However, high resolution CCDs are not readily available due to the high costs associated with these types of devices. Thus, it would be desirable to provide a high resolution scanner at a low production cost for use by a variety of users.
The primary object of the present invention is to provide a high resolution scanning mechanism for use with a conventional CCD to increase the resolution of the CCD when scanning documents, transparencies and photographs.
Another object of the present invention is to provide an adaptor that can be coupled to a motorized, light receiving device for adapting the device to scan images at high resolutions.
Yet another object of the present invention is to provide a control program for use in a scanner central processing unit to control a motorized high resolution scanning mechanism to scan documents at high resolutions within a conventional scanner.
The present invention is a mechanism and method high resolution scanning within a conventional scanner, using a conventional CCD-type image processing device. The mechanism, when incorporated with a conventional light receiving device, provides high resolution images achieved at less cost in relation to other high resolution CCD scanner-type elements. The present device includes a telescoping mechanism within the light receiving seat for adjusting the distance between the lens and the CCD. The lens and CCD are located movably on a light-receiving guide. The light-receiving guide is mounted on a pair of rails within the light-receiving device, which run perpendicular to the rails connected to the light-receiving seat. The light-receiving guide is connected by a drive belt to a motor that can shift the light-receiving guide along the rails from a central position to either end. When the light-receiving device is moved to an off-center position, the light-receiving device lens may be telescopically advanced to zoom in on a smaller area to be scanned. Thus, the light-receiving device may be employed to scan columns comprising a smaller width of the object to be scanned. Software provided with the scanning device stores each column from the object to be scanned within memory. After the scanner scans in a first column of data, the light-receiving device then returns. The light receiving guide moves along the rails within the light-receiving device advancing to a second column position. When the object has been completely scanned, software within the scanner provides the necessary means for combining the columns of data into one image. With each column scanned at the conventional resolution, the combined image from the columns is at a higher resolution. The resolution achieved from two columns is greater than in normal scanning methods using the same CCD. Thus, a low cost, high resolution scanner is achieved using a conventional CCD. In addition, the mechanism provides a way for upgrading existing scanners to include a high resolution capability by exchanging the existing light receiving seat and software with the present invention.